Microbiological tests for the identification and/or counting of organisms have been developed. Such tests are commonly performed in laboratories in hospitals and medical clinics and the like. In one such known test, a minimum inhibiting concentration (MIC) is obtained by exposing an organism to different dilutions of an antibiotic and analyzing which dilution level is sufficient to kill and/or inhibit growth the organism.
Such MIC test is commonly done in a tray containing a regular pattern of small wells usually arranged in rows and columns. In one such tray, for example, there may be twelve rows and seven columns of wells for a total of 84 wells. Other trays may have a different number of wells. Each row of wells may contain different antibiotic in dilutions which are typically graded with scores in levels of the power of two, e.g. 1, 2, 4, 8, 16, 32 and 64, or some other sequence of numbers.
A technician commences such MIC test by employing a tray in which the wells contain antibiotics with progressive concentrations and then adds a growth solution containing the organism in each of the wells. After an incubation period, the technician visually analyzes the wells to determine at which antibiotic concentration (the MIC) the organism appears to have been killed and/or growth inhibited. This analysis is done visually by scanning a row of wells containing a particular antibiotic and noting in which well the solution appears, for example, cloudy, opaque or clear. The technician does this analysis for each row and assigns a score value to his analysis by noting on a corresponding form carrying score value notations which well in the row contained the minimum inhibitory concentration.
The trays of wells usually are transparent so that the technician may observe the test wells against a light or dark background. In other microbiological tests the tray may include in some of the wells various components which, when innoculated with the specimen solution, react with certain organisms in a particular manner. These wells, when analyzed and appropriately evaluated by the technician, provide an identification of the organism.
In a typical laboratory environment a large number of such organism analyses must be performed. This often results in a fatigue of the technician who has to constantly look at tiny test wells and becomes prone to note the wrong score value on the score form and would welcome a procedure which would simplify the analysis and evaluation with less chance for error and with greater speed.